Self-propelled adjustable tractor mole



July 17, 1962 s. A. DILDAY 3,044,749

SELF-PROPELLED ADJUSTABLE TRACTOR MOLE Filed Nov. 3, 1959 Fig. 4 54 32 32 INVENTOR. SIDNEY A. DILDAY 3,044,749 Patented July 17, 1962 3,044,749 SELF-PROPELLED ADJUSTABLE TRACTOR MOLE Sidney A. Dilday, 3820 Arnold Ave., San Diego, Calif. Filed Nov. 3, 1959, Ser. No. 850,555 Claims. (Cl. 254-1345) Another object of this invention is to provide a tractor mole having extended ski nose portions which span obstructions, cross pipes, or breaks in the pipe and prevent the mole from jamming.

Still another object of this invention is to provide a tractor mole which is adjustable to and self-aligning in various sizes of pipes, over a Wide range.

A further object of this invention is to provide a tractor mole which, with suitable sealing of the drive motors, can be operated in water filled pipes.

Finally, it is an object to provide a tractor mole of the aforementioned character which is simple, safe and convenient to operate and which will give generally efficient and durable service.

With these and other objects definitely in view, this invention consists in the novel construction, combination and arrangement of elements and portions, as will be hereinafter fully described in the specification, particularly pointed out in the claims, and illustrated in the drawing which forms a material part of this disclosure, and in which:

FIGURE 1 is a side elevation view of the complete tractor mole;

FIGURE 2 is a top plan view thereof;

FIGURE 3 is a sectional view taken on the line 3-3 of FIGURE 2 and showing the mole inside a pipe assembly; and

FIGURE 4 is an end elevation view as taken from the left end of FIGURE 3.

Similar characters of reference indicate similar or identical elements and portions throughout the specification and throughout the views of the drawing.

The mole comprises a pair of flat, elongated, somewhat resilient arms which, for the purposes of description, will be referred to as an upper arm 10 and a lower arm 12, said arms being interconnected at one end to form a rigid tail portion 14, to which is fixed a tow ring 16. The arms 10 and 12 diverge from the tail portion 14 and are curved slightly inwardly, the lower arm 12 being substantially longer than the upper arm 10 and said arms having inwardly curved, tapered ski nose portions 18 and 20, respectively. The precise shape of the ski nose portions 18 and 20 is not critical, that illustrated being one satisfactory form.

Mounted on the inside of the upper arm 10 adjacent the ski nose portion 13 is a drive motor 22 having a gear unit 24 driving a pair of resilient drive wheels 26, of rubber or the like, on opposite sides of said arm. Mounted on the inside of the lower arm 12 is a second drive motor 28 having a gear unit 30 driving a further pair of drive wheels 32 on opposite sides of the lower arm. The rims of the drive wheels 26 and 32 project outwardly beyond their respective arms 10 and 12 and the drive motors 22 and 28 are positioned at a similar distance from the tips of the ski nose portions 18 and 21 so that one pair of drive wheels is staggered longitudinally relative to the other pair. The drive motors 22 and 28 '14 and have their axes perpendicular to the axes are unidirectional since only forward drive is needed, although the drive wheels are preferably provided with free-wheeling means to compensate for differences in rotational speeds. Suitable insulated conductors 34 supply electrical power to the'drive motors 22 and'28: and can be secured to the inside of arms 10 and 12 by conventional wiring clips 36.

Fixed between the arms 10 and 12 at the tail portion 14 is a wedge shaped mounting block 38, to which is secured a transversely extending, resilient stabilizing bar 40, having at each end a freely rotatable stabilizing wheel 42 carried in a bearing 44. The stabilizing wheels 42 are spaced equally on opposite sides of the tail portion of the drive wheels 26 and 32.

The arms 10 and 12 are biased apart by a pair of bowed leaf springs 46, which are pivotally connected adjacent their ends by a pin 48. The forward ends of the leaf springs 46 are riveted or otherwise secured to the inside of the arms 10 and 12, while the rear ends thereof are engaged by a double ended jack screw 50, which, when turned, separates or brings together the ends of the leaf springs. Thus by means of the single jack screw 50, the spread of the arms 10 and 12 can be controlled.

The mole is used to carry a cable such as indicated at 51, cleaning device or other equipment through an otherwise inaccessible pipe or conduit. The jack screw 50 is first adjusted to space the arms 10 and 12, so that the drive wheels 26 and 32 bear frictionally on opposite portions of the wall of the pipe 52, illustrated in FIGURE 3. When the mole is inserted into the pipe 52, the stabilizing wheels 42 bear on the inside of the pipe, generally diametrically, at right angles to the drive wheels 26 and 32, the mole thus being longitudinally stabilized in the direction of motion. The stabilizing bar 40 has sufiicient resiliency to adjust for various sizes of pipes, the pressure required on the stabilizing wheels 42 not being excessive. The drive motors 22 and 28 are then actuatedto propel the mole along the pipe.

To illustrate the practicability of the mole, a pipe junction has been illustrated, comprising a T-connection 54 and branch pipe 56, the junction creating an opening 58 in the side of the passage of pipe 52. When the mole approaches such an opening 58, the ski nose portion 20 on the longer lower arm 12 bridges the opening, as in FIG- URE 3, the inwardly curved end preventing jamming in the opening. The upper drive wheels 26 continue to drive, so that the lower arm 12 slides across the opening 58 until the lower drive wheels 32 climb back onto the pipe wall and resume driving. If the upper arm 10 encounters an opening, the lower drive wheels 32 continue to drive until the opening is passed, the longitudinally staggered driving units enabling the mole to pass all such obstructions. Apart from exceptional circumstances, such as a virtual blockage of the pipe, the mole is capable of overcoming many different types of obstructions, since one pair of drive wheels is normallyin driving contact with the pipe wall and olfset from the area of obstruction which may afiect the other pair of drive wheels.

While the arms 10 and 12 have been referred to as the upper and lower arms, it should be understood that the mole can operate in any orientation in a pipe, the combination of opposed drive wheels and stabilizing wheels providing automatic centering and alignment. The structure is simple, light in weight and compact, which greatly facilitates handling in restricted spaces, such as in excavations. Although size and proportions are not critical and may be varied to suit dilferent requirements, one particular mole is adjustable to fit pipes from eight to twenty inches in diameter. The distance which the mole'will travel is limited only by the run of the pipe, length of the power supply conductors and load to be pulled, moderate turns or bends in the pipe presenting no problem. By the simple expedient of sealing the drive motors 22 and 28 and using waterproof conductors 34, the mole may be used in water filled pipes.

The operation of this invention will be clearly comprehended from a consideration of the foregoing description of the mechanical details thereof, taken in connection with the drawing and the above recited objects. It will be obvious that all said objects are amply achieved by this invention.

It is understood that minor variation from the form of the invention disclosed herein may be made without departure from the spirit and scope of the invention, and that the specification and drawing are to be considered as merely illustrative rather than limiting.

I claim:

1. A tractor mole, comprising: a pair of substantially resilient, elongated arms interconnected at one end and diverging from the connection; said arms each having an inwardly curving ski nose portion at the other end thereof; one of said arms being substantially longer than the other; a pair of frictional drive wheels mounted on each of said arms; said drive wheels being disposed adjacent said ski nose portions and rotatable on generally parallel axes normal to the longitudinal axis of said arms; the edges of said drive wheels projecting outwardly of said arms; driving means operatively connected to turn said drive wheels; a resilient stabilizing bar fixed to said arms at the interconnection thereof and extending outwardly therefrom on both sides; freely rotatable stabilizing wheels mounted on opposite ends of said stabilizing bar on axes normal to the axes of said drive wheels.

2. A tractor mole, comprising: a pair of substantially resilient, elongated arms interconnected at one end and diverging from the connection; said arms each having an inwardly curving ski nose portion at the other end thereof; one of said arms being substantially longer than the other; a pair of frictional drive wheels mounted on each of said arms; said drive wheels being disposed adjacent said ski nose portions and rotatable on generally parallel axes normal to the longitudinal axis of said arms; the edges of said drive wheels projecting outwardly of said arms; driving means operatively connected to turn said drive wheels; one pair of said drive wheels being longitudinally staggered relative to the other pair; a resilient stabilizing bar fixed to said arms at the interconnection thereof and extending outwardly therefrom on both sides; freely rotatable stabilizing wheels mounted on opposite ends of said stabilizing bar on axes normal to the axes of said drive wheels.

3. A tractor mole, comprising: a pair of substantially resilient, elongated arms interconnected at one end and diverging from the connection; said arms each having an inwardly curving ski nose portion at the other end thereof; one of said arms being substantially longer than the other; a pair of frictional drive wheels mounted on each of said arms; said drive wheels being disposed adjacent said ski nose portions and rotatable on generally parallel axes normal to the longitudinal axis of said arms; the

edges of said drive wheels projecting outwardly of said arms; an individual drive motor connected to each pair of said drive wheels; one pair of said drive wheels being longitudinally staggered relative to the other pair; a resilient stabilizing bar fixed to said arms at the interconnection thereof and extending outwardly therefrom on both sides; freely rotatable stabilizing wheels mounted on opposite ends of said stabilizing bar on axes normal to the axes of said drive wheels.

4. A tractor mole, comprising: a pair of substantially resilient, elongated arms interconnected at one end and diverging from the connection; said arms each having an inwardly curving ski nose portion at the other end thereof; one of said arms being substantially longer than the other; a pair of frictional drive wheels mounted on each of said arms; said drive wheels being disposed adjacent said ski nose portions and rotatable on generally parallel axes normal to the longitudinal axis of said arms; the edges of said drive wheels projecting outwardly of said arms; an individual drive motor connected to each pair of said drive wheels; one pair of said drive wheels being longitudinally staggered relative to the other pair; a resilient stabilizing bar fixed to said arms at the interconnection thereof and extending outwardly therefrom on both sides; freely rotatable stabilizing wheels mounted on opposite ends of said stabilizing bar on axes normal to the axes of said drive wheels; spring means mounted between and engaging said arms to bias the arms apart; and adjusting means connected to said spring means to control the bias thereof.

5. A tractor mole, comprising: a pair of substantially resilient, elongated arms interconnected at one end and diverging from the connection; said arms each having an inwardly curving ski nose portion at the other end there of; one of said arms being substantially longer than the other; a pair of frictional drive wheels mounted on each of said arms; said drive wheels being disposed adjacent said ski nose portions and rotatable on generally parallel axes normal to the longitudinal axis of said arms; the edges of said drive wheels projecting outwardly of said arms; an individual drive motor connected to each pair of said drive wheels; one pair of said drive wheels being longitudinally staggered relative to the other pair; a resilient stabilizing bar fixed to said arms at the interconnection thereof and extending outwardly therefrom on both sides; freely rotatable stabilizing wheels mounted on opposite ends of said stabilizing bar on axes normal to the axes of said drive wheels; 2. pair of leaf springs mounted between said arms and pivotally interconnected intermediate their ends; said leaf springs being connected at one end to said arms; and an adjusting screw engaging the other ends of said leaf springs to adjust the separation of the leaf springs and bias said arms apart.

Goetz Dec. 16, 1913 Boucher July 22, 1952 

